As long time Alaskan boaters, we agree heaters are important! We have stayed away from propane in large part because you''d need a lot of storage. You didn''t indicate the size of the boat but it''s typical for a diesel heater to burn a gallon every 10-15 hours, think of the equivalent in propane. Unless you just use it briefly at the end of the day to take the chill off you''ll be lugging propane cylinders a lot. We like drawing fuel
out of the main tank for that reason but your use may be less.
We have had 3 different espars and think the new models in particular are very nice. We have also had a small bulkhead diesel heater (like a Taylor, only it was a Hi-Seas) and it did OK on a 28'' boat. The ends got cold and there would be specks of soot on the deck in the morning which we cleaned off periodically.
The big advantage of the espar type heater is they reduce condensation, as they suck in outside air, heat it (which dries it) and blow it around. We woke up earlier this fall to frost on the decks, toasty warm and zero condensation. Bulkhead heater won''t do that but they are much easier to install.